CHARACTERIZATION OF GROWTH DIFFERENTIATION-FACTOR-5 (GDF-5) AS A NEUROTROPHIC FACTOR FOR CULTURED NEURONS FROM CHICKEN DORSAL-ROOT GANGLIA/

Growth/differentiation factor-5 (GDF-5), a morphogenetic protein, has previously been shown to act as a neurotrophic factor for midbrain dop aminergic neurons. To further elucidate the neurotrophic potential of GDF-5, serum free cultures of dorsal root ganglionic (DRG) neurons fro m developing chick embryos were treated with GDF-5 with or without the simultaneous addition of other trophic factors. Our results show that GDF-5 has a minor promoting effect on its own, but it can enhance the survival promoting effect of neurotrophin-3 (NT-3) and nerve growth f actor (NGF) on cultured DRG neurons. Our finding fits well into the co ncept that neurotrophic factors may act synergistically in ensuring su rvival of different neuronal populations. The capacity of GDF-5 to red uce the requirement of a subpopulation of sensory neurons for NT-3 may have implications for the treatment of peripheral neuropathies. (C) 1 997 Elsevier Science Ireland Ltd.